Investing in the stock market is often considered a game of chance, and the only generally accepted advice is to “buy low and sell high.” However, there is data involved with the stock market, and the right apps can make it more accessible to those who need it. Whether you’re a developer or trader, it’s important to understand stock market data APIs and determine which are the best for your needs.
Stock market data APIs provide a stream of data to finance and decentralized applications, lending all the information necessary to display accurate numbers and help end users make better decisions.
It’s a great tool, but before you choose one to incorporate, it’s important to ask yourself: “Which stock market APIs are best?” And how do you choose between them when building a finance application, including decentralized finance (DeFi)? Multiple factors may affect which API you choose, which is why it’s crucial to know what to look for. Below, this article will explain what you need to know about stock market APIs and offer a list of the top stock market data APIs currently available.
What Is a Stock Market Data API?
In the programming world, API stands for “application programming interface.” It is a kind of interface designed to connect apps or other systems, often to exchange meaningful data in a streamlined way. A stock market data API, more specifically, is designed to parse vital financial data from markets all over the world so that it can be readily transmitted, exchanged, and eventually utilized by end users who need financial data to make better decisions.
As a programmer of a financial app, if you need access to market data, you only have two main options. You can either figure out a way to write your own complex code for parsing raw data from every major stock exchange and crypto exchange — or you can make use of a stock market API that already exists and functions well.
The latter option is much less expensive and much easier, which is partially why financial market data is now a more-than-$30 billion industry.
What Makes a Stock Market API Worth Using?
What makes a stock market data API worth using over another one? That’s a great question, and it really boils down to personal preference and need. All APIs are going to offer data, but you have to decide if it’s the kind of data you need and if it’s compatible with the rest of your financial app.
These are some of the most important variables we’re going to consider when evaluating different stock market data APIs:
Real-time and historical data
Do you need stock market data in real-time, as prices fluctuate in response to new information? Do you need market data as it’s been reported historically, so you can track how prices have changed over time? You’ll probably need both if you’re building a financial app. Not every API pulls data in real-time, and not every API offers historical data. We favor APIs that can do both.
Exchange and asset class access
It’s important to ask yourself: What financial data do you need? There are many different exchanges, including exchanges outside of the United States, so it usually pays to choose a stock market API that has access to as many as possible. You also need to think about access to data for different types of asset classes, such as equities, crypto, bonds, and ETFs. Depending on the application, you may need a tool that can do it all.
Exchanges and aggregated data
When a stock market API pulls data to provide to end users, does it derive that data from a single exchange or from an aggregated pool of different sources? These can lead to slightly different outputs, so it’s usually best to have an API that can do both.
Adjusted and unadjusted historical prices
It’s also important to think about the difference between adjusted and unadjusted historical prices. In some cases, corporate actions can retroactively change the closing price of a given stock; for example, after a stock split, a stock may present an “adjusted close.” Do you need a stock exchange that provides both adjusted and unadjusted historical prices?
Language support
You should also consider the language support inherent in each tool. If your app is based in Java, your API needs to be compatible. Ideally, your stock market API will support whatever programming language you choose to use for your app.
Overall ease of use
Why not make your job a little bit easier? Some APIs are super streamlined, making them easier for developers to integrate.
The Best Stock Market Data APIs for Financial and Decentralized Applications
These are some of the best stock market data APIs available today:
Alpha Vantage
Alpha Vantage is a stock market data API that’s been backed by Y Combinator. It’s currently a free, open-source API for financial data. For the past several years, Alpha Vantage has been the “intel inside” data feed for over 500 open-source libraries on GitHub, with support for many programming languages like Python, Java, and JavaScript.
With it, engineers can tap into both real-time and historical data on stocks, ETFs, mutual funds, and cryptocurrency. It also processes derived financial data, including more than 50 different technical indicators, to help investors further. Most developers find it both robustly functional and easy to use. Alpha Vantage is also a leading data provider for blockchain oracles by serving as the “data bridge” between the decentralized world and conventional capital markets.
Zirra
With Zirra, you can tap into the power of artificial intelligence (AI) to gather the financial data you need in a sensible way. This API provides real-time data and more than 100 time series signals for 16,000 (and growing) companies. It also pulls data from the past, providing historical data from 2014 onward. Zirra also has access to several secondary metrics and data points, such as media sentiment. Zirra also provides cryptocurrency-related news feeds.
QuoteMedia
If you’re looking for an enterprise product designed to provide financial data at scale, you might consider QuoteMedia. This tool is customized on a per-client basis, so you can get a functional and reliable data stream that’s perfectly suited to your specific needs. You’ll get all the information you need, filtered exactly how you require, and you’ll also get access to ample support once deployed. QuoteMedia’s data universe includes equities, mutual funds, commodities, forex, and cryptocurrency.
Xignite
Xignite is another API that was “built by developers, for developers,” and it’s designed to make it easy to incorporate real-time financial data into your latest applications. It offers coverage for almost every imaginable asset class, including equities, ETFs, crypto, options, futures, and even credit markets. It also relies on a diverse mix of data sources and curates its own set of high-quality data to ensure you and those using your app always have the information needed.
Polygon.io
Uninitiated investors might imagine there’s only one stock exchange — but in reality, there are more than 10 in the United States alone. Polygon is a stock API that attempts to simplify the process of aggregation, so you can get a reliable, accurate stock quote while simultaneously considering data from all exchanges at once. It also offers individual, exchange-specific price quoting.
IEX Cloud
Another convenient tool for financial data developers is IEX Cloud, which offers both first-party data (directly from the exchange) and third-party data (from various sources). Like many of the APIs on this list, IEX Cloud provides both historical and real-time data, and it offers data streams on a wide range of different asset classes across many different exchanges.
Bloomberg API
You’ve likely heard of Bloomberg Terminals — the computer software system that enables financial professionals to access, monitor, and analyze real-time financial market data and place trades. So why not consider using a more modern version in the form of Bloomberg API? With it, you can get access to real-time data from many different exchanges for as long as you’re a paying Bloomberg customer.
The Bottom Line — Making the Right Decision For You
As a developer, you owe it to yourself to choose a financial data API that’s functional and easy to use, and you owe it to your eventual end users to choose an API capable of providing a reliable stream of millions of different data points.
Fortunately, you have plenty of options available to you. Remember to compare the type of data they collect, whether that’s real-time, historical, aggregated, or from a single exchange. It’s also important to think about access to data for different types of asset classes. Ensure the API you choose offers the financial data you need.
Compare these APIs carefully so you can pick the best interface for your upcoming fintech or DeFi applications. Choosing the right API can save you time and money, especially when comparing the task to creating your own from scratch. You’ll save countless hours of development time, but make sure you still end up with an option that meets your needs and standards.
